Engines used in motor vehicles typically have a pump in some form which provides lubrication to the engine bearings, as well as other components of the engine. Typically, these oil pumps are driven directly or indirectly by the crankshaft of the engine, and do not have very complex pressure regulation systems. While these systems generally are sufficient, there are several disadvantages. Most notably, because of the simplicity of the pressure regulation system, control over the output of the oil pump and fluid delivery to the various engine parts is somewhat limited.
One example of this lack of control is that there are certain engine operating conditions where the maximum amount of oil flow is not needed for the various engine components. However, because of the lack of flexibility of control of the oil pump, the oil pressure may exceed what is needed under these various operating conditions, which leads to excessive power consumption by the oil pump, and reduced efficiency of the engine. This is mainly because the design of the oil pump is usually in such a manner that, under all engine operating conditions, the oil pump attempts to deliver higher levels of oil pressure and flow required for worst case conditions.
Accordingly, there exists a need for a method of control of a variable flow pump, by using an engine control unit which actuates a solenoid for either direct or indirect control of the oil pump.